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. 2023 Mar 3;10:1097609. doi: 10.3389/fmolb.2023.1097609

FIGURE 1.

FIGURE 1

Map of gal operon and the 3′ and 5′end-sharing mRNA. P1 and P2 are the two promoters of the gal operon of Escherichia coli which are separated by five nucleotides. Numbers indicate gal nucleotide residue coordinates, where one is the start of transcription from the P1 promoter. The number at the end of each gene belongs to the last nucleotide of the stop codon of that gene. Six nucleotides downstream of the stop codon of the galM gene is a 17-nucleotide inverted repeat sequence (head-to-head arrows) that forms the terminator hairpin (red) that terminates transcription and protects the full-length galETKM mRNA from 3′→5′ exonuclease digestion. Two DNA probes, E and K (500 bp) (underlines) used in the Northern blots are presented. The galETKM operon produces two kinds of mRNA groups: 3′ end-sharing and 5′ end-sharing. The 3′ end-sharing mRNA shares the same 3′ end with the full-length galETKM mRNA. The 5’end-sharing mRNA shares the same 5′ end with the galETKM mRNA. The E and K probes were used to detect the 5′end-sharing and 3′ end-sharing mRNA, respectively. Spot 42 (green) binds at the translation initiation region of the galK gene. Thus, Spot 42 binds to multiple mRNAs.